Packaging of high-frequency chips, such as GaN-on-SiC chips, which may, for example, be used in power amplifier modules, is particularly challenging because one needs to address issues with electromagnetic discontinuities, thermal management, and cost. Currently, existing methods of chip integration into waveguide rely on a eutectic die attach into a machined waveguide that features a pedestal to position the chip at the right level within the waveguide. The eutectic solder (made of, e.g., AuSn) is a poor thermal conductor (with a thermal conductivity of about 50 W/mK), and the die attach suffers from reliability and planarity issues. Further, this is a serial pick-and-place type mounting, which may suffer from placement accuracy and is costly. Furthermore, the waveguide pedestal needs to be specifically machined to accurate dimensions, which increases manufacturing costs and reduces reliability.
Integration of high-power RF front-ends for radar systems, communications systems, and the like, also present a thermal management challenge. For example, a comparable phased array heat exchanger may add about 7 inches in height and about 100 lbs in weight to a communications system, which may be prohibitive for use in compact radars and unmanned aerial vehicles (UAVs).
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention, and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art.